The present invention relates to an actuator arrangement for a twin-clutch transmission which has a first and a second partial transmission, with the first partial transmission containing odd forward gear stages and with the second partial transmission containing even forward gear stages, having at least one first and one second selector drum which have in each case one controllable drive motor and at least one control cam, with each control cam being assigned at least one cam follower, with it being possible for the cam followers to be connected in each case to a selector sleeve of an associated shift clutch pack in order to engage and disengage gear stages of the twin-clutch transmission.
1. Prior Art                Selector drums which, in a shift transmission, axially move a sliding block, a roller or a similar cam follower, and thereby a shift fork which is connected to the cam follower, by means of a control cam or curved track (selector drum groove) or a bead, in order to engage or disengage a gear by means of a shift clutch.        Selector drum systems having one or more selector drums.        Motorcycle transmission having selector drum actuation.        Principle structure and function of a twin-clutch transmission (DKG) or powershift transmission having two clutches and two partial transmissions connected thereto, with it being possible for transmission stages and therefore individual gears or gear stages of the twin-clutch transmission to be realized by means of fixed wheels and loose wheels which can be connected in a rotationally form-fitting manner by means of shift clutches.        Selector drum systems having two selector drums and one wheel set arrangement, in which the even gears are served by the one roller and the odd gears are served by the other roller (DE 198 40 621 C2; DE 199 20 440 C2).        Selector drums having an encircling groove (DE 199 24 335 A1).        Use of at least two selector drums for a twin-clutch transmission (EP 1 182 376 A2; DE 101 28 854 A1).        Prior art pursuant to § 3(2) PatG: DE 103 61 356.0: selector drum having a movable groove flank.        Use of a selector drum for a twin-clutch transmission (DE 101 28 854 A1, EP 0 831 256 B1; DE 30 37 990 A1).        
Selector drum systems which allow gears to be skipped (primarily during downshifts) or the engagement of two gears simultaneously by means of axially moveable selector drums, adjusting members, force-loaded switch points or controlled switch points or corresponding groove sections (DE 101 28 854 A1, DE 196 38 269 A1, EP 0 831 256 B1, DE 199 24 335 A1, DE 195 09 477 A1, DE 195 43 645 A1).
2. Disadvantages of the Prior Art
Firstly, a skipping gears in multiple shifts (for example 6→3, 5→2 etc.) is a problem in particular in a twin-clutch transmission. When using a selector drum actuating arrangement having a selector drum, and in particular also when using a selector drum actuating arrangement having two selector drums with the separation of the even gears being situated on one selector drum and the odd gears being situated on the other roller, multiple shifts of said type are generally possible only if intermediate gears are “passed through”, that is to say are also engaged and disengaged. “Passing through” the gears is necessary in order to be able to carry out subsequent single upshifts, with possible tractive force bridging, according to an expedient shift sequence logic.
Example:Selector drum 01 (SCHW—01): R-1-3-5  Partial transmission 1Selector drum 02 (SCHW—02): 2-4-6  Partial transmission 2
Here, if a tractive downshift 5-2 is to be directly carried out, specifically with tractive force bridging, that is to say without an interruption in tractive force, the following takes place: before the actual “gearshift” can take place by merging (crossfading) between the clutches, that is to say by means of a transfer of torque from the partial transmission 1 to the partial transmission 2, on SCHW_02, which according to the selector drum logic is in the 4th gear or in neutral between the 4th and 6th gears or in 6th gear, initially the 6th gear is to be disengaged and the 4th gear is to be engaged and disengaged or only the 4th gear is to be disengaged, and then the 2nd gear is to be subsequently engaged.
Only then can the torque transfer take place. Finally, SCHW_01 must then disengage the 5th gear or even additionally engage and possibly again disengage the 3rd gear in order to be able to subsequently directly carry out a possible 2-1 or 2-3 shift with tractive force bridging. SCHW_01 must accordingly be “tracked” (must follow).
Secondly, in the prior art, therefore, the gears cannot be directly freely selected in relation to one another, and it is therefore not possible for every driver demand, or every driving situation, to be optimally fulfilled or covered.
A lack of direct selection freedom in the event, for example, of multiple downshifts entails a considerable degree of additional expenditure in terms of time. The acceleration capability of a vehicle demanded for example by a 5-2 or 6-3 shift is therefore slowed, since, as described, gears must additionally be engaged or disengaged and only a purely sequential shift sequence is possible, respectively.
Thirdly in terms of functionality, the selector drum actuating arrangement is therefore considerably more disadvantageous than other shift actuating arrangements, in particular than a hydraulic shift actuating arrangement with individual rods, that is to say a shift unit having one actuator per gear pair or selector sleeve.
Fourthly, passing through the gears, or the tracking of the gears, likewise leads to an additional loading of the synchronizing units and thereby to a reduction of service life.
Fifthly, only by considerably increasing the structural expenditure or increasing the installation space demand and costs is it possible, with a selector drum actuating arrangement having two selector drums according to the prior art, to carry out only some of the possible, relevant direct multiple shifts as stated above.